Qualified international subscribers can receive full issues of High-Performance Composites and Composites
Technology delivered in a convenient and interactive digital magazine format. Read at your convenience on your desktop or mobile device.

The partnership between JRTL, Composite Tooling & Engineering Solutions Ltd. (CTES, Matlock, UK) and Retrac Composites Ltd. (Swindon, UK) has produced a way of repairing composite tools, which saves both time and money. It’s thought the solution will also enable the partners to carry out repairs for the aerospace industry on site in the future, wherever the client is based.

Faced with the prospect of weeks of tracking down a large autoclave or oven to accommodate a large, composite tool that requires repair, CTES and Retrac turned instead to JRTL to supply eight infrared lamps and a hot-bonding controller with multiple heater mats.

These allowed engineers to control accurately the cure of the additional prepreg laminate in multiple areas at the same time and cut the curing time of the surface sealer from 18 hours to 1.5 hours.

The tool in question measures almost 14m in length and weighs 2.75 metric tons. The geometry of the tool didn’t allow for the sole use of the controller, so infrared lamps were brought into service to apply heat locally in complex areas of the tool. Local vacuum bags were used to apply pressure in all repair areas.

Paul Rogger, technology director of JRTL, explains, “Retrac and CTES had limited time to repair the tool, so we’re pleased we’ve been able to help them come up with a solution. The combination of the lamps and the hot-bonding controller gave them the control they required for the cure cycle they needed to do a repair. It was also portable, so if there’s a requirement for this sort of thing in the future, clients purchasing these items from us will be able to carry out repairs on site.”

Liam Moloney, director at CTES, says, “We previously had no other way of getting enough heat into the job if we needed to cure anything on the surface of the tool without using either a very large oven or autoclave. Finding an appropriately sized autoclave or constructing an oven from scratch would have been very time-consuming and costly. I’ve been amazed by how much time this has saved, and the accuracy in terms of controlling the temperature throughout each cure has been second to none.”

Ian Drew, project director of Retrac Composites Ltd., says, “This is the culmination of 18 months’ work as part of a significant contract with GKN Aerospace. These tools are vital in the manufacture of the rear wing spar, so when they need to be repaired or go in for maintenance you want to be reassured they’ll come out able to do the job. CTES offered us this solution and I’m delighted to see how well it’s worked.”